1. Technical Field of the Invention
The present invention relates to piezoelectric components, and more particularly, to piezoelectric components including a piezoelectric resonator vibrating in a longitudinal vibration mode, such as an oscillator, a discriminator, and a filter.
2. Description of the Related Art
FIG. 16 is a side view of a piezoelectric component relating to preferred embodiments of the present invention. A piezoelectric component 1 includes a substrate 2. On one surface of the substrate 2, pattern electrodes (not shown) are disposed. A piezoelectric resonator 3 is mounted on the substrate 2. The piezoelectric resonator 3 includes a base member 4 as shown in FIG. 17. Two external electrodes 5a and 5b are provided on one side surface of the base member 4. The base member 4 has, for example, a structure in which piezoelectric layers and electrodes are laminated along the longitudinal direction of the base member 4. The piezoelectric layers are polarized in the longitudinal direction of the base member 4. The laminated electrodes are connected to the external electrodes 5a and 5b. When a signal is applied between the external electrodes 5a, 5b, an electric field is applied in the longitudinal direction of the base member 4. When the electric field is applied, the piezoelectric layers expand and contract to generate a longitudinal vibration in a basic mode in the base member 4.
At the center of the base member 4 along the longitudinal direction thereof, support members 6a and 6b made from an electrically conductive material are mounted on the two external electrodes 5a and 5b. To mount the piezoelectric resonator 3, the support members 6a and 6b mounted on the external electrodes 5a and 5b, are bonded via electrically conductive adhesive 7 to pattern electrodes disposed on the substrate 2. Therefore, when a signal is input to the pattern electrodes, a longitudinal vibration is excited in the base member 4. Since the support members 6a and 6b are mounted at the center of the base member 4, which serves as a node during generation of the longitudinal vibration, the vibration of the base member 4 is prevented from being suppressed or hindered.
Because the piezoelectric component 1 must be compact, it is necessary that the piezoelectric resonator 3 is compact. Therefore, in order for the piezoelectric resonator 3 having the above structure to be compact, the support members 6a and 6b must be small. When the support members 6a and 6b are small, areas where the adhesive 7 is applied to bond the support members 6a, 6b to the pattern electrodes on the substrate 2 become small and a sufficient bonding strength is not obtained. When the amount of the adhesive 7 is increased to obtain a high bonding strength, the adhesive 7 flows out from the bottom surfaces of the support members 6a, 6b as shown in FIG. 16, and the adhesive 7 may contact between the two support members 6a and 6b to cause a short circuit between the support members 6a , 6b.